page_title: Methylidyne radical
section_title: Bonding
hierarchical_section_title: Methylidyne radical / Bonding
caption_attribution_description: English: chemical structure of HCCo3(CO)9
context_page_description: Methylidyne, or carbyne, is an organic compound whose molecule consists of a single hydrogen atom bonded to a carbon atom. It is the parent compound of the carbynes, which can be seen as obtained from it by substitution of other functional groups for the hydrogen.
  The carbon atom is left with either one or three unpaired electrons, depending on the molecule's excitation state; making it a radical. Accordingly, the chemical formula can be CH• or CH3•; each dot representing an unpaired electron. The corresponding systematic names are methylylidene or hydridocarbon, and methanetriyl or hydridocarbon. However, the formula is often written simply as CH.
  Methylidyne is a highly reactive gas, that is quickly destroyed in ordinary conditions but is abundant in the interstellar medium.
context_section_description: As an odd-electron species, CH is a radical. The ground state is a doublet (X²Π).  The first two excited states are a quartet (with three unpaired electrons)  (a⁴Σ⁻) and a doublet (A²Δ). The quartet lies at 71 kJ/mol above the ground state. 
  Reactions of the doublet radical with non-radical species involves insertion or addition:
  [CH]•(X²Π) + H
  ₂O → [CHO]• + H
  ₂ or [CH
  ₂(OH)]•
  whereas reactions of the quartet radical generally involves only abstraction:
  [CH]3•(a⁴Σ⁻) + H
  ₂O → [CH
  ₂] + [HO]•
  Methylidyne can bind to metal atoms as tridentate ligand in coordination complexes. An example is methylidynetricobaltnonacarbonyl HCCo
  ₃(CO)
  ₉.
caption: HCCo
  3(CO)
  9, a metal cluster complex with a methylidyne ligand.
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